Oris I Sanjur

Smithsonian Tropical Research Institute, Ciudad de Panamá, Panamá, Panama

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Publications (29)86.47 Total impact

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    ABSTRACT: Landscape changes occurring in Panama, a country whose geographic location and climate have historically supported arbovirus transmission, prompted the hypothesis that arbovirus prevalence increases with degradation of tropical forest habitats. Investigations at four variably degraded sites revealed a diverse array of potential mosquito vectors, several of which are known vectors of arbovirus pathogens. Overall, 675 pools consisting of 25,787 mosquitoes and representing 29 species from nine genera (collected at ground and canopy height across all habitats) were screened for cytopathic viruses on Vero cells. We detected four isolates of Gamboa virus (family: Bunyaviridae; genus: Orthobunyavirus) from pools of Aedeomyia squamipennis captured at canopy level in November 2012. Phylogenetic characterization of complete genome sequences shows the new isolates to be closely related to each other with strong evidence of reassortment among the M segment of Panamanian Gamboa isolates and several other viruses of this group. At the site yielding viruses, Soberanía National Park in central Panama, 18 mosquito species were identified, and the predominant taxa included Ad. squamipennis, Coquillettidia nigricans, and Mansonia titillans.
    No preview · Article · Feb 2016 · The American journal of tropical medicine and hygiene
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    ABSTRACT: Two variants of the Neotropical mangrove species Pelliciera rhizophorae distributed along both sides of the Isthmus of Panama were detected by different colouration of the floral bracts and the size of the floral and vegetative structures. These findings raised questions concerning a possible speciation event in P. rhizophorae, for which a series of macro- and microscopic morphological traits (reproductive and vegetative structures), molecular markers from plastid DNA and climatic profiles were analyzed. Samples of P. rhizophorae were collected in three localities from the Panamanian Caribbean and Pacific coasts. The data obtained from molecular markers and morphological traits showed significant differences between the variants. The climatic profiles showed contrasting characteristics of rainfall and temperature in their habitats: variant A is found in wetter zones and variant B occupies drier zones. Evidence suggesting that a process of incipient speciation has occurred in P. rhizophorae in response to ecogeographical isolation due to climatic factors is presented. The presence of two geographically separate genetic-morphological groups, adapted to contrasting climatic conditions, will be the basis for suggesting the existence of incipient lineages in Pelliciera. © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2015, ●●, ●●–●●.
    No preview · Article · Oct 2015 · Botanical Journal of the Linnean Society
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    ABSTRACT: The present study shows new evidence of morphological traits that supports the hypothesis of diversification between two genetic variants of Pelliciera rhizophorae (Tetrameristaceae), the most ancient species in the Neotropical mangrove ecosystem. Previous studies using molecular markers identified two variants of this species. Our new study, using pollen grain morphology, revealed differences in pollen sculpture between the two variants; that is, in Variant A the exine is characterised as perforate–verrucose, while in Variant B, it is punctuate. Pollen size in Variant A is larger than in Variant B, whereas the exine is thicker in Variant B than in Variant A. The differences in pollen morphology between the two variants represent new evidence suggesting that a diversification process might be occurring within P. rhizophorae, possibly due to adaptive processes in response to environmental conditions or pollination vectors.
    No preview · Article · Jul 2015 · Palynology
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    ABSTRACT: We assessed the reproductive ecology of the American crocodile (Crocodylus acutus) on Coiba Island, Panama from January–December 2013. We examined nest site characteristics from January–April and hatchling survivorship from April–December. Ten nests were examined at three nesting localities where 30% of the nests were found under forest canopies and 70% were exposed to sunlight (distance to nearest tree = 280 ± 110 cm). Half of the nests were built closer to the sea and the other half closer to bodies of freshwater (700 ± 360 cm). The nest dimensions were 17.5 ± 7.8 cm from the top of the clutch to the surface, 2.9 ± 9.9 cm from the bottom of the clutch to the surface, and 35.9 ± 3.6 cm wide at the top of the nest cavity. The average soil conditions in the nests consistently had high concentrations of potassium (69.3 mL/L) and manganese (9.2 mg/L), moderate concentrations of phosphorus (6.6 mg/L) and iron (3.7 mg/L), and low concentrations of zinc (0.5 mg/L) and copper (0.0 mL/L). Cation exchange capacity showed consistently high concentrations of calcium (2.2 cmol/kg), moderate of magnesium (1.1 cmol/kg), and low in aluminum (0.1 cmol/L). Volumetric water content was about 25.0 ± 2.6% at the bottom and 22.8 ± .3% in the middle of the clutches. Hatching success was 88.9%, of which 68.3% hatched by themselves or with the mother’s aid and 20.6% hatched with our aid. Mean size of the mother was 219 ± 6.2 cm total length (TL) and 115.9 ± 3.0 cm snout–vent length (SVL). The incubation period was estimated to be 85–88 days. TL and SVL growth rate of those individuals were 0.03–0.16 cm/day and 0.00–0.09 cm/day, respectively. Population size was estimated to be 218.6 hatchlings in 22.4 km2; the hatchling population declined 65.7% after the first 2 months (May and June) and 95.9% by July, leaving only 0.5% remaining by December. This is the first study to assess nest-site characteristics and estimate hatchling survival in a Pacific population of American crocodiles.
    Full-text · Article · Apr 2015 · South American Journal of Herpetology
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    ABSTRACT: The Central American Isthmus (CAI) is an important geographic barrier in the Neotropics. Its role in the diversification of marine and coastal species has been detected in fishes, turtles, sea urchins, and mangroves. We evaluated the CAI’s influence on the diversification of the most ancient neotropical mangrove species Pelliciera rhizophorae across populations from the Caribbean and Pacific coasts, based on the analysis of ten nuclear microsatellite loci and two noncoding chloroplast DNA regions. The two molecular markers showed concordant patterns of diversification in this mangrove species. Contrary to our expectations, this study did not reveal significant genetic structure among populations separated by the CAI. Two major genetic variants (cluster I and cluster II) were found on both coasts, but the two were not found intermixed in the same population. Within each coastal region, breaking of gene flow among populations was found at two points in the Pacific Basin and one point in the Caribbean Basin, separating the Colombian and Panamanian populations. Our study revealed a transisthmian connection among populations of P. rhizophorae. This result, together with the reduced genetic diversity in the Caribbean reported in our previous study, suggests the recent origin of these populations, probably due to reintroduction of P. rhizophorae from the Pacific coast. Taking into account that these introductions are random events, this study raises a new question: Why are genetic variants not intermixed within the Caribbean populations? Our hypotheses suggest the influence of environmental factors and/or anthropogenic impact on the establishment of these Caribbean patches.
    Full-text · Article · Dec 2014 · Tree Genetics & Genomes
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    ABSTRACT: We conducted nocturnal surveys in the insular and coastal areas of Coiba National Park (CNP) and its mainland buffer zone in Panama (Chiriquí conservation site) from 2009–2012 to determine the conservation status of Crocodylus acutus. In 99 nights, we surveyed 147.2 km and captured 185 animals during nocturnal transects inspection with headlamps. Overall, sex ratio was 1.00:1.01 female/male with significant differences by size/age class and year. Females were slightly larger in total length than males (115.1 ± 56.9 cm-females, 105.4 ± 71.8 cm-males). The encounter rate was calculated based on number of animals captured per km of surveyed transect. The C. acutus encounter rate per year was 1.8 ind/km (60 ind/33.5 km/12 places visited) in 2009, 1.0 ind/km (90 ind/87.4 km/18 places visited) in 2010, and 1.3 ind/km (35 ind/26.3 km/8 places visited) in 2012. Based on our spatial analysis, the animals showed a dispersed pattern in most sites on CNP. Captured C. acutus were found in 581.1 km2 total area within 78% natural habitat, including mangroves and beaches, and 22% disturbed habitat on both the mainland and the islands. In addition, the spatial analysis showed reduction in natural land cover; crocodile habitat showed limited conversion to agricultural land use; and we found correlation between crocodile population size and protected areas. The differences between mainland and island populations regarding ecology suggest that a long-term monitoring program for American Crocodiles is necessary to distinguish between natural fluctuations and anthropogenic changes on population dynamics and conservation status.
    Full-text · Article · Dec 2014 · Journal of Herpetology
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    ABSTRACT: It is difficult to overstate the cultural and biological impacts that the domestication of plants and animals has had on our species. Fundamental questions regarding where, when, and how many times domestication took place have been of primary interest within a wide range of academic disciplines. Within the last two decades, the advent of new archaeological and genetic techniques has revolutionized our understanding of the pattern and process of domestication and agricultural origins that led to our modern way of life. In the spring of 2011, 25 scholars with a central interest in domestication representing the fields of genetics, archaeobotany, zooarchaeology, geoarchaeology, and archaeology met at the National Evolutionary Synthesis Center to discuss recent domestication research progress and identify challenges for the future. In this introduction to the resulting Special Feature, we present the state of the art in the field by discussing what is known about the spatial and temporal patterns of domestication, and controversies surrounding the speed, intentionality, and evolutionary aspects of the domestication process. We then highlight three key challenges for future research. We conclude by arguing that although recent progress has been impressive, the next decade will yield even more substantial insights not only into how domestication took place, but also when and where it did, and where and why it did not.
    Full-text · Article · Apr 2014 · Proceedings of the National Academy of Sciences
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    Full-text · Chapter · Jan 2014
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    Full-text · Dataset · Oct 2013
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    ABSTRACT: The Global Genome Biodiversity Network (GGBN) was formed in 2011 with the principal aim of making high-quality well-documented and vouchered collections that store DNA or tissue samples of biodiversity, discoverable for research through a networked community of biodiversity repositories. This is achieved through the GGBN Data Portal (http://data.ggbn.org), which links globally distributed databases and bridges the gap between biodiversity repositories, sequence databases and research results. Advances in DNA extraction techniques combined with next-generation sequencing technologies provide new tools for genome sequencing. Many ambitious genome sequencing projects with the potential to revolutionize biodiversity research consider access to adequate samples to be a major bottleneck in their workflow. This is linked not only to accelerating biodiversity loss and demands to improve conservation efforts but also to a lack of standardized methods for providing access to genomic samples. Biodiversity biobank-holding institutions urgently need to set a standard of collaboration towards excellence in collections stewardship, information access and sharing and responsible and ethical use of such collections. GGBN meets these needs by enabling and supporting accessibility and the efficient coordinated expansion of biodiversity biobanks worldwide.
    Full-text · Article · Oct 2013 · Nucleic Acids Research
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    ABSTRACT: Anopheles punctimacula s.l. is a regional malaria vector in parts of Central America, but its role in transmission is controversial due to its unresolved taxonomic status. Two cryptic species, An. malefactor and An. calderoni, have been previously confused with this taxon, and evidence for further genetic differentiation has been proposed. In the present study we collected and morphologically identified adult female mosquitoes of An. punctimacula s.l. from 10 localities across Panama and one in Costa Rica. DNA sequences from three molecular regions, the three prime end of the mitochondrial cytochrome c oxidase I gene (3' COI), the Barcode region in the five prime end of the COI (5' COI), and the rDNA second internal transcribed spacer (ITS2) were used to test the hypothesis of new molecular lineages within An. punctimacula s.l. Phylogenetic analyses using the 3' COI depicted six highly supported molecular lineages (A-F), none of which was An. malefactor. In contrast, phylogenetic inference with the 5' COI demonstrated paraphyly. Tree topologies based on the combined COI regions and ITS2 sequence data supported the same six lineages as the 3' COI alone. As a whole this evidence suggests that An. punctimacula s.l. comprises two geographically isolated lineages, but it is not clear whether these are true species. The phylogenetic structure of the An. punctimacula cluster as well as that of other unknown lineages (C type I vs C type II; D vs E) appears to be driven by geographic partition, because members of these assemblages did not overlap spatially. We report An. malefactor for the first time in Costa Rica, but our data do not support the presence of An. calderoni in Panama.
    Full-text · Article · Jun 2013 · Acta tropica
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    ABSTRACT: Tapirs (Tapirus sp.) have been studied extensively in the wild, yet little is known about their fundamental reproductive biology, information that is critical to establishing self-sustaining populations in captivity as a hedge against extinction. This paper reviews information on the reproductive biology of the 4 species of tapirs: Baird's (Tapirus bairdii), lowland (T terrestris), mountain (T pinchaque) and Malayan (T indicus). Both sexes reach puberty between 14 and 48 months of age. Behaviorally, tapirs display few overt signs of estrus, and external signs of pregnancy are not evident until approximately 2 months before parturition. Immunoassay techniques to measure reproductive hormones in blood and urine have been validated for tapirs, which allow monitoring of ovarian cycle activity and pregnancy. Data indicate that females are polyestrous, with an estrous cycle length of approximately 30 days. The exception is the Malayan tapir, which exhibits 2 types of cycles: short (approximately 1 month) and long (approximately 2 months). Gestation length is approximately 13 months and females can conceive at the first post-partum cycle within 1 month after birth. Good quality ejaculates have been obtained via electroejaculation in the Baird's and Malayan tapir and the sperm from Baird's tapir cryopreserved using standard cryodiluents, although more work is needed to optimize these protocols. Given that all 4 species of tapir most likely will continue to be maintained in captivity, effective genetic management is vital for long-term survival. Optimization of assisted reproductive technologies, including sperm cryopreservation and artificial insemination, could benefit the genetic management of tapirs.
    No preview · Article · Mar 2013 · Integrative Zoology
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    ABSTRACT: Free-ranging ticks are widely known to be restricted to the ground level of vegetation. Here, we document the capture of the tick species Amblyomma tapirellum in light traps placed in the forest canopy of Barro Colorado Island, central Panama. A total of forty eight adults and three nymphs were removed from carbon dioxide–octenol baited CDC light traps suspended 20 meters above the ground during surveys for forest canopy mosquitoes. To our knowledge, this represents the first report of questing ticks from the canopy of tropical forests. Our finding suggests a novel ecological relationship between A. tapirellum and arboreal mammals, perhaps monkeys that come to the ground to drink or to feed on fallen fruits.
    No preview · Article · Jan 2013
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    ABSTRACT: Free-ranging ticks are widely known to be restricted to the ground level of vegetation. Here, we document the capture of the tick species Amblyomma tapirellum in light traps placed in the forest canopy of Barro Colorado Island, central Panama. A total of forty eight adults and three nymphs were removed from carbon dioxide–octenol baited CDC light traps suspended 20 meters above the ground during surveys for forest canopy mosquitoes. To our knowledge, this represents the first report of questing ticks from the canopy of tropical forests. Our finding suggests a novel ecological relationship between A. tapirellum and arboreal mammals, perhaps monkeys that come to the ground to drink or to feed on fallen fruits.
    Full-text · Article · Jan 2013 · F1000 Research
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    ABSTRACT: Como parte de la región de Baja Centroamérica, la biodiversidad acuática endémica de Panamá exige una atención particular en cuanto a su conservación. Los peces de agua dulce del género Gephyrocharax actualmente incluyen tres especies reconocidas y descritas que viven en quebradas y ríos panameños, pero los límites de las especies de este género no han sido examinados con rigor. La delimitación precisa de las especies es un primer paso, crítico en la protección de la biodiversidad. La detección de los límites de las especies es especialmente importante para los grupos de organismos que habitan en ambientes sensibles sujetos a la degradación reciente, tales como las aguas continentales de las regiones tropicales. Por otra parte, los hábitats de las especies de este género se están deteriorando rápidamente. Se realizó un estudio molecular preliminar con base en dos regiones del ADN mitocondrial para: i) examinar la variación genética en el rango de distribución del género en Panamá, ii) probar los límites de las especies y iii) deducir las relaciones filogenéticas dentro de Gephyrocharax. Nuestro análisis se fundamenta en los genes mitocondriales ATPasa 8 y 6 a partir de muestras existentes en la Colección de Peces Neotropicales del Smithsonian Tropical Research Institute. Los resultados obtenidos contribuyen a la interpretación de las relaciones filogenéticas y el proceso de especiación de las tres especies panameñas reconocidas del género Gephyrocharax. Además se ha encontrado evidencia molecular de la presencia de una nueva especie sin describir en la región del Pacífico occidental de Panamá. También se redefinió el área de distribución conocida de estas especies. Toda esta información es de gran importancia para los esfuerzos de conservación a través de la asignación de unidades de gestión genética dentro de un contexto evolutivo.
    Full-text · Conference Paper · Sep 2012
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    ABSTRACT: The completion of the land bridge between North and South America approximately 3.5-3.1 million years ago (Ma) initiated a tremendous biogeographic event called the Great American Biotic Interchange (GABI), described principally from the mammalian fossil record. The history of biotic interchange between continents for taxonomic groups with poor fossil records, however, is not well understood. Molecular and fossil data suggest that a number of plant and animal lineages crossed the Isthmus of Panama well before 3.5 Ma, leading biologists to speculate about trans-oceanic dispersal mechanisms. Here we present a molecular phylogenetic analysis of the frog genus Pristimantis based on 189 individuals of 137 species, including 71 individuals of 31 species from Panama and Colombia. DNA sequence data were obtained from three mitochondrial (COI, 12S, 16S) and two nuclear (RAG-1 and Tyr) genes, for a total of 4074 base pairs. The resulting phylogenetic hypothesis showed statistically significant conflict with most recognized taxonomic groups within Pristimantis, supporting only the rubicundus Species Series, and the Pristimantis myersi and Pristimantis pardalis Species Groups as monophyletic. Inference of ancestral areas based on a likelihood model of geographic range evolution via dispersal, local extinction, and cladogenesis (DEC) suggested that the colonization of Central America by South American Pristimantis involved at least 11 independent events. Relaxed-clock analyses of divergence times suggested that at least eight of these invasions into Central America took place prior to 4 Ma, mainly in the Miocene. These findings contribute to a growing list of molecular-based biogeographic studies presenting apparent temporal conflicts with the traditional GABI model.
    Full-text · Article · Dec 2011 · Molecular Phylogenetics and Evolution
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    ABSTRACT: The pathogenic chytrid fungus, Batrachochytrium dendrobatidis, has been implicated as the main driver of many enigmatic amphibian declines in neotropical sites at high elevation. Batrachochytrium dendrobatidis is thought to be a waterborne pathogen limited by temperature, and the extent to which it persists and causes disease in amphibians at lower elevations in the neotropics is not known. It also is unclear by what mechanism(s) B. dendrobatidis has emerged as a pathogenic organism. To test whether B. dendrobatidis is limited by elevation in Panamá, we sought to determine the prevalence and intensity of B. dendrobatidis in relation to anuran abundance and diversity using quantitative PCR (qPCR) analyses. Sites were situated at varying elevations, from 45 to 1215 m, and were at varying stages of epizootic amphibian decline, including pre-epizootic, mid-epizootic, 2 years post-epizootic, and 10 years post-epizootic. Batrachochytrium dendrobatidis was found in all sites regardless of elevation or stage of epizootic decline. Levels of prevalence and infection intensity were comparable across all sites except at the mid-epizootic site, where both prevalence and intensity were significantly higher than at other sites. Symptoms of chytridiomycosis and corresponding declines in amphibian populations were variably seen at all elevations along a post-epizootic gradient. Because it is inherently difficult to prove a negative proposition, it can neither be proven that B. dendrobatidis is truly not present where it is not detected nor proven that it is only recently arrived where it is detected. Thus, there will always be doubts about whether B. dendrobatidis is enzootic or invasive. In any case, our results, coupled with current knowledge, suggest most clearly that the disease, chytridiomycosis, may be novel and invasive, and that the pathogen, B. dendrobatidis either is, or is becoming, globally ubiquitous.
    Full-text · Article · Dec 2011 · EcoHealth
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    ABSTRACT: We review previous studies on the genetic diversity of malaria vectors to highlight the major trends in population structure and demographic history. In doing so, we outline key information about molecular markers, sampling strategies and approaches to investigate the causes of genetic structure in Anopheles mosquitoes. Restricted gene flow due to isolation by distance and physical barriers to dispersal may explain the spatial pattern of current genetic diversity in some Anopheles species. Nonetheless, there is noteworthy disagreement among studies, perhaps due to variation in sampling methodologies, choice of molecular markers, and/or analytical approaches. More refined genealogical methods of population analysis allowing for the inclusion of the temporal component of genetic diversity facilitated the evaluation of the contribution of historical demographic processes to genetic structure. A common pattern of past unstable demography (i.e., historical fluctuation in the effective population size) by several Anopheles species, regardless of methodology (DNA markers), mosquito ecology (anthropophilic vs zoophilic), vector status (primary vs secondary) and geographical distribution, suggests that Pleistocene environmental changes were major drivers of divergence at population and species levels worldwide.
    Full-text · Article · Aug 2011 · Infection, genetics and evolution: journal of molecular epidemiology and evolutionary genetics in infectious diseases
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    ABSTRACT: Most bees rely on flowering plants and hence are diurnal foragers. From this ancestral state, dim-light foraging in bees requires significant adaptations to a new photic environment. We used DNA sequences to evaluate the phylogenetic history of the most diverse clade of Apoidea that is adapted to dim-light environments (Augochlorini: Megalopta, Megaloptidia and Megommation). The most speciose lineage, Megalopta, is distal to the remaining dim-light genera, and its closest diurnal relative (Xenochlora) is recovered as a lineage that has secondarily reverted to diurnal foraging. Tests for adaptive protein evolution indicate that long-wavelength opsin shows strong evidence of stabilizing selection, with no more than five codons (2%) under positive selection, depending on analytical procedure. In the branch leading to Megalopta, the amino acid of the single positively selected codon is conserved among ancestral Halictidae examined, and is homologous to codons known to influence molecular structure at the chromophore-binding pocket. Theoretically, such mutations can shift photopigment λ(max) sensitivity and enable visual transduction in alternate photic environments. Results are discussed in light of the available evidence on photopigment structure, morphological specialization and biogeographic distributions over geological time.
    Full-text · Article · Jul 2011 · Proceedings of the Royal Society B: Biological Sciences
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    ABSTRACT: Among crocodilians, Crocodylus rhombifer is one of the world's most endangered species with the smallest natural distribution. In Cuba, this endemic species coexists with the American crocodile (Crocodylus acutus). Hybridization between these two species is well known in captivity and might occur in the wild, but has never been demonstrated genetically. Here, we combined molecular data with environmental, geographic, and fossil data to infer the evolutionary history of Crocodylus in the Cuban Archipelago, and to evaluate genealogical support for species boundaries. We analyzed seven microsatellite loci plus DNA sequence data from nuclear (RAG-1) and mitochondrial (cytochrome b and cytochrome oxidase I) genes from 89 wild-caught individuals in Cuba, Grand Cayman Island, Jamaica, and Central America, and two samples from zoo collections. Microsatellites showed evidence of introgression, suggesting potential hybridization among Cuban groups. In Cuba, C. acutus contained one mitochondrial DNA (mtDNA) haplotype, whereas C. rhombifer contained two haplotypes. MtDNA data showed that C. acutus is paraphyletic with respect to C. rhombifer, revealing 1% sequence divergence between species within Cuba vs. 8% divergence between Cuban forms and mainland C. acutus. We suggest that hybridization has been a historical as well as a current phenomenon between C. acutus and C. rhombifer. These findings suggest that long-term conservation of crocodiles in Cuba will require identification of genetically pure and hybrid individuals, and a decrease in anthropogenic activities. We also recommend more extensive morphological and genetic analyses of Cuban population to establish clear boundaries of the hybrid zone between C. acutus and C. rhombifer.
    Full-text · Article · Jul 2011 · Journal of Experimental Zoology Part A Ecological Genetics and Physiology